A torque control method for permanent magnet synchronous motor

Abstract

The invention provides a torque control method of a permanent magnet synchronous motor. When the motor is in a low-speed section, an open-loop torque control method is used to control the torque of the motor, that is, a calibration method is used to obtain the correspondence between the given torque and the Q-axis current The relationship is fitted into a curve, and the Q-axis current is directly obtained from the given torque; when the motor is in the high-speed field weakening area, the closed-loop torque control method is used to estimate the output power of the controller through the D, Q-axis current and voltage, and the The output power is divided by the motor speed to obtain the feedback torque. The PI regulator is formed between the feedback torque and the given torque. The output value of the PI regulator is the given current of the Q-axis. It does not rely on the rated parameters of the motor. With the operating conditions of the motor, it collects the current and voltage of the DQ axis of the motor in real time to estimate the output power of the motor controller, avoiding the problem that the inductance parameters under the rated working conditions cannot accurately reflect the essence of the motor parameters. At the same time, the method performs delay compensation and dead zone compensation on the collected DQ axis voltage, so as to obtain accurate DQ axis voltage and then obtain accurate power estimation.

Description

technical field [0001] The invention relates to the field of automation control, in particular to a method for controlling the torque of a permanent magnet synchronous motor. Background technique [0002] In recent years, with the rapid development of power electronics technology, microelectronics technology, new motor control theory and rare earth permanent magnet materials, permanent magnet synchronous motors have been rapidly popularized and applied. Compared with the traditional electric excitation synchronous motor, the permanent magnet synchronous motor, especially the rare earth permanent magnet synchronous motor has the advantages of less loss, high efficiency and obvious power saving effect. The permanent magnet synchronous motor provides excitation with permanent magnets, which makes the structure of the motor relatively simple, reduces the cost of processing and assembly, and saves the collector ring and brush that are prone to problems, which improves the reliabi...

AI Technical Summary

Problems solved by technology

In other words, the inductance parameter of the permanent magnet synchronous motor is not constant, but changes with the change of the operating condition of the motor. The inductance parameter at the rated working condition cannot accurately reflect the essence of the motor parameter.

[0004] Starting from the torque equation of a synchronous machine, accurate inductance parameters must be obtained in order to achieve precise torque control, which is difficult to achieve in practical applications

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